A number of systems for converting sunlight to electricity are known. One such system that has proven useful in efficiently producing electricity from the sun's radiation is described in U.S. Pat. No. 4,691,076. In that system, an array is formed of semi-conductor spheres. Each sphere has a P-type interior and an N-type skin. A plurality of the spheres are housed in a pair of aluminum foil members which form the contacts to the P-type and N-type regions. The foils are electrically insulated from one another and are flexible. Multiple arrays can be interconnected to form a module of solar cell elements for converting sunlight into electricity.
In order to produce sufficient quantities of the arrays, it is necessary to have a process for their manufacture that is uncomplicated, low cost and efficient. An uncomplicated system would be one using currently available technology constructed in such a way that the applicable process steps can be conducted in a highly repeatable manner. Moreover, the less complicated the process steps, generally the more cost effective will the entire process be carried out. Finally, the more repeatable the process, the more efficiently the operation and the higher production of solar arrays.
A key process step in the making of silicon solar cells is the ability to isolate shorted silicon spheres in a solar array. There are few known techniques for locating and then isolating shorted silicon spheres in a solar cell. One prior art method required probing each sphere to determine whether the sphere had shorted to the foil. This technique is excessively laborious and while it can be automated, it nevertheless then required a complex and time consuming method of either physically removing the shorted sphere or covering it with an electrically insulating material. Isolating the sphere using the latter technique was hard to control and found to be ineffective.